The present invention is related to surgical working platforms. More specifically, the present invention relates to a working platform and method for using the same which facilitates the alignment of surgical and observational instruments into a patient.
In the treatment of some diseases or defects associated with a patient, it has been found necessary to access specific targets within a patient. In the treatment of some diseases of or defects of human beings, it has been found necessary to access specific portions of the brain. Currently there are several methods for inserting surgical and observational instruments into a patient""s brain.
U.S. Pat. No. 3,055,370 issued to McKinney et al. shows one currently used method for placing a surgical instrument to access a specific portion of the brain. The surgical instrument of the ""370 patent includes a ball which has a bore. The direction of the bore can be changed. The instrument has an elongated tube of a specific length. A stylet is inserted within the tube to access the globus pallidus and perform a pallidotomy. An opening or burr hole is made in the skull at a specific landmark on the skull. Next, X-rays are taken in the fore-and-aft (AP) and lateral positions, and the line of the bar is projected downwardly by a ruler both in the fore-and-aft (AP) and lateral positions, so that the direction of the needle can be determined before it is inserted. When the direction of the longitudinal axis of the tubular member is determined to be satisfactory, a holder is threaded further into a tap to force a surface against a ball and lock a tubular member into place. Alignment of the trajectory is not measurable along a specific line occurring at the intersection of two planes. Alignment is dependent on placement of the burr hole at a specific location to determine one plane. X-rays are used to determine another plane-based use of common landmarks on the skull. The end result is that an educated guess is being used to position the stylet at the globus pallidus for the pallidotomy. One shortcoming with the method of using X-ray imaging to direct a surgical or observational instrument, is that many of the destinations within a patient are not viewable via X-ray. Another shortcoming relates to the slight shifting of intracranial contents, once a burr hole is placed and the dura and arachnoid are penetrated. Once cerebrospinal fluid is released via the burr hole, the intracranial contents (i.e. brain) may shift one or more millimeters. In such a case, the calculated trajectory is no longer accurate. Hence, there is an inherent inaccuracy with the described scheme.
Several other methods are also used to place instruments, catheters, or observational tools into patients. Currently, surgical procedures are performed through craniotomy flaps or craniotomy burr holes. A burr hole of about 14 mm is made in the skull. Needles or probes are typically passed through the burr hole into the brain using framed stereotaxy, frameless stereotaxy or freehand without stereotaxy.
The freehand method depends very heavily on the knowledge and judgment of the surgeon. In the freehand method, the surgeon determines the insertion point with a couple of measurements from a known landmark. The surgeon then looks at the measured point, makes adjustments, determines the angle of insertion and then inserts the surgical instrument or tool.
In framed stereotaxy, a ring frame is mounted to the patient""s skull by multiple (typically three or four) pins or screws. This ring frame is used to determine a three dimensional data set. From this data set, Cartesian coordinates are calculated for both the lesion, the location of the pins or screws, and the fiducial marks on the frame. The ring frame fits into a large frame. A large frame is then attached to the patient in the operating suite. The large frame provides known positions and guides the surgical or observational instruments. The large frame is used to position the instrument to be introduced into the patient through a burr hole so that it intersects the target. In frameless stereotaxy, the ring frame is replaced with several markings on the patient""s skull which can be used to determine several known positions. The large frame is replaced by a camera. The camera is usually infrared or some such device. Multiple sensors readable by the camera are placed on the instrument. For example, the surgical instrument or tool is provided with one or more light emitting diodes (xe2x80x9cLEDsxe2x80x9d) which are tracked by the camera. The position of the surgical instrument can be calculated from the information from the LEDs on the surgical instrument or observational tool.
U.S. Pat. Nos. 4,955,891 and 4,805,615, both issued to Carol each discuss the use of stereotaxy surgery with computerized tomographic (xe2x80x9cCTxe2x80x9d) scanning. CT scanning is used to determine the exact position of a lesion or specific portion of the brain. After the exact position of the lesion or specific portion of the brain is determined, a phantom fixture is set up. The phantom fixture replicates the position of the ring frame on the patient. A phantom target is set up. The instrument can then be positioned on the phantom such that it intersects the target. The information from the phantom can then be used in actually positioning the instrument in the operating suite.
U.S. Pat. No. 4,998,938 issued to Ghajar et al. shows another surgical device for facilitating the insertion of an instrument into a patient""s cranial cavity through a burr hole. The device includes a guide having an end configured to pass into the burr hole. There is a separate locking member. A body member includes alignment markings to help with insertion of a catheter or stylet. Unlike the ""370 patent, there is no movable member for adjusting the path of the guide.
The methods currently in use all have a number of shortcomings. Most of the techniques currently used to place a surgical instrument or observational tool within a patient employ a limited amount of accuracy. In particular, current framed, frameless, and freehand methods compute or predict trajectories on the basis of imaging data or anatomic landmarks that do not account for the slight, but real shifting of the brain upon opening the cranium and meninges to the level of the subarachnoid space. This inherent inaccuracy inherently limits the success of these various methodologies. In other words, these systems do not use any means of updating the data files to include data obtained following the placement of a surgical burr hole and opening of the meninges. In addition, all the methods require large amounts of judgment on the part of the surgeon placing the surgical instrument or tool, and in particular, offer no direct feedback on the success or failure of the trajectory to reach the target. Very few of the techniques use an imaging or scanning apparatus to aid in the placement of the surgical instrument or observational tool. The only one that does requires a phantom frame and target to be set up to simulate the real geometry. In short, none of the apparatuses appear to use an imaging or scanning apparatus as extensively as they could be used to minimize the time and effort needed to accurately place a surgical instrument into a patient, and to offer immediate data on the success or failure of the trajectory to reach the target.
Still another disadvantage is that the apparatuses used today are not remotely controlled or actuated. In some operating environments, the patient is not accessible to the surgeon. Therefore, it is advantageous to have remote control of the tool. One such environment is within an MR magnet associated with an MR operating suite. When the patient is in an open magnet, the surgeon may have direct access to the patient. When in a closed magnet, the surgeon probably will not have such direct access to the patient.
A surgical method and apparatus for accurately aligning the trajectory of, guiding of, and introducing or withdrawal of an instrument is disclosed. The apparatus includes a base which has a movable member movably attached to the base. The movable member has a passage therein which forms a portion of the trajectory path. The movable member also includes a guide stem which has an opening therein. The guide stem is attached to said movable member such that the opening in the guide stem substantially aligns with the passage in the movable member. The movable member can include either an integral guide stem for holding the positioning stem or a removably attached guide stem. In the case of the former, a positioning stem is inserted into the opening of the guide stem for purposes of trajectory alignment. In the case of the latter, the removably attached guide stem can be removed and replaced with a positioning stem.
A positioning stem further includes a first locator and a second locator. The first and second locators are associated with two different portions of the positioning stem so that they are essentially two points on a line. The first and second locators are also locatable by a scanning or imaging system. The positioning stem is either inserted into the guide stem that is integral to the movable member, or is removably attached to said movable member and used to position the movable member. Moving the positioning stem while either within the guide stem or removably attached to the movable member also moves the passage therein to different trajectories. Once the passage within the movable member more or less is aligned with a target within the body, a locking member locks the movable member into a fixed position.
In one embodiment the first locator and the second locator are readable by a magnetic resonance imaging apparatus. The locator can include a fluid readable by a magnetic resonance imaging apparatus or a source of radio frequency, such as a coil, which is readable by a magnetic resonance imaging apparatus. In the latter embodiment, the first and second locators may be small radio frequency (RF) coils that detect an electromagnetic signal in a magnetic resonance imaging environment. The electromagnetic signal detected can be used to locate the first and second locators. The line formed by the first locator and the second locator may be substantially aligned with the centerline of the passage in the movable member or may be offset from the centerline of passage in the movable member. In other embodiments, the first and second locators may be light emitting diodes which are readable by an infrared camera.
The first and second locators may be located within an essentially solid plastic positioning stem, or in another embodiment, the first and second locators may be located within an MR-visible chamber within the positioning stem. In the latter embodiment, the chamber may be filled with an MR-visible fluid (paramagnetic, for example), which can be used to afford a first approximation of alignment. The first and second locators may be either MR-visible (different than the MR-visible chamber) or may be MR-invisible, in which case they would exhibit a negative image against the background of the MR-visible fluid within the larger chamber of the positioning stem. Advantageously, the fluid in the chamber produces an image which can be easily located and can be used to roughly align the positioning stem. The MR-visible or MR-invisible fluid of the first and second locators can then be used for fine or precise alignment.
In the embodiment where the guide stem and positioning stems are removably attached to the movable member, the movable member can include a threaded opening which receives either the guide stem or the positioning stem. In this embodiment where the guide stem is interchangeable with the positioning stem, one end of both the guide stem and positioning stem is threaded. A portion of the passage in the movable member has internal threads for receiving the threaded end of either the guide stem or the positioning stem. In the embodiment where the guide stem is formed as part of the movable member, the positioning stem fits within the opening in the guide stem. The movable member is a ball capable of swiveling with respect to the base.
In another embodiment, the movable member may also include a stage which allows for planar movement in a direction intersecting the trajectory. A surgical instrument, such as a needle, probe (cryotherapy probe, laser probe, RF ablation probe, microwave interstitial therapy probe, or focussed ultrasound therapy probe), catheter, endoscope, or electrode, can then be inserted through the movable member and the opening in said guide stem to guide the instrument toward the target position within the patient. In this embodiment, it is possible to reposition the surgical instrument without altering the trajectory itself, by first withdrawing it from the targeted tissue and then adjusting the stage in a direction intersecting the trajectory.
It is advantageous to have the trajectory guide operable from a remote location. Among the advantages is that the patient will not have to be moved in and out of an environment in order to make adjustments to the trajectory guide. Adjustments or use of the trajectory guide does not have to be interrupted when used in an environment where a surgeon or technician does not have access to the trajectory guide on the patient. This shortens the time spent for the surgical procedure which is appreciated by both the surgeon or technician as well as the patient. It should also be noted that the trajectory guide is also adaptable to other environments such as for use in a CT scan environment. In CT scanning, x-radiation is used in order to form the images. Overexposure to x-rays is harmful to patients who are undergoing procedures. Overexposure to x-rays is a concern to surgeons or technicians who perform these procedures. Therefore, it is advantageous to have the capability to maneuver the trajectory guide from a remote location so that the procedure can be done in a shorter amount of time and so that the physicians and technicians that may be using the trajectory guide can keep exposure to various imaging environments to a minimum.
In a first preferred embodiment of a remotely controlled trajectory guide, there is the actual trajectory guide and a remote trajectory guide. The remote trajectory guide is a duplicate of the actual trajectory guide. The remote trajectory guide has the same look and feel as the actual trajectory guide so that the surgeon or technician used to using the actual guide can move the remote guide as if it was the actual guide attached to the patient. The objective is to make the movement of the remote feel as though it was the actual guide. In this way, once the physician surgeon or the technician learns to use the actual guide they do not have to learn how to use the remote device. In the first embodiment, the tilt or trajectory defined by the trajectory guide and the advancement and of the surgical instrument is provided for by using a mechanical device using a cable or filament.
In a second preferred embodiment of a remotely controlled trajectory guide, a first hydraulic cylinder and a second hydraulic cylinder control actuators which may be used to position the positioning member. Once so positioned and after the movable member locked is locked, thereby also locking in the trajectory, the first and second hydraulic cylinder control actuators may be removed. A third hydraulic cylinder and actuator may then be used to control the insertion or withdrawal of an instrument. The hydraulic cylinders are especially useful for positioning the movable member and inserting or withdrawing the instrument when the patient is positioned remotely from the surgeon. Although many scanning devices allow access to a patient, there are many styles of scanning devices that do not allow access to the patient during a scanning operation. For example, in an MRI type scanning device, the magnet producing the magnetic field can be of several shapes. Some of the magnets are shaped such that a patient must be positioned out of reach of the surgeon in order to be within the homogeneous imaging volume of the magnetic field during a scanning operation.
In operation, a target within a patient is initially selected. A surgical opening into the body is made and the base is inserted into and surgically secured to the opening. The movable member and outer locking ring are also removably attached to the base. The positioning stem is then used to move the movable member and the passage therein to form a trajectory toward the target. The first locator portion and the second locator portion are read by the scanning device to determine the trajectory represented by the line of the positioning stem. The positioning stem is moved until the line represented by the positioning stem intersects the selected target. The positioning stem can be moved manually or by using the first hydraulic cylinder and actuator, and the second hydraulic cylinder and actuator. The line of the positioning stem may also be offset from the target in an alternate embodiment. Of course, the determination of the position of the first and second portions of the positioning stem is performed at least in part by the central processing unit and the memory of the scanning device. Once alignment is indicated, the movable member is locked into position which locks the trajectory represented by the positioning stem. The positioning stem is then removed either from the guide stem that is integral to the movable member, or, when the guide stem is not integral with the movable member, from the movable member itself in the latter case, a guide stem is then attached to the movable member. The opening in the guide stem and the substantially aligned passage in the movable member form a trajectory in line with the selected target. The instrument is passed therethrough.
The third hydraulic cylinder and associated actuator can be used to control insertion or withdrawal of the instrument, if remote operation is desirable. Insertion or withdrawal can also be done manually. In situations where the target may be quite small, if the surgical instrument, upon successfully reaching the quite small target, reveals that the target selected, due to anatomic variance, is indeed not the true target, repositioning of the surgical instrument can be made by means of a slight offset. In such a situation, a stage can be moved so that a parallel trajectory can be followed. In such a situation, it may be advantageous and safer to employ a stage in order to minimize surgical trauma to the tissues.
The opening within the movable member and guide stem (whether integral to the movable member or removably attached) are designed to accommodate surgical instruments and observational tools. As there is a wide variety of different surgical instruments and observational tools, it is anticipated that multiple movable members and guide stems with openings of different diameter for such a wide array of surgical instruments and observational tools will be employed. In addition, in the case of a guide stem that is integral to the movable member, additional positioning stems of similar diameters to fit appropriately into the guide stems will be employed.
Advantageously, the scanning device used for diagnostic purposes can be employed to place an instrument within the body of a patient. There is no need for framed stereotaxy or unframed stereotaxy, two procedures which require large amounts of time to perform. Procedures that formerly required many hours can now be performed in substantially less amounts of time with the trajectory guide. Time is saved over framed or unframed stereotaxy since there is no need to spend time placing a frame onto the patient or calculating the location of several selected points before the actual introduction of a surgical instrument. The procedure is not only quicker, but provides for real time feedback as the surgical instrument progresses into the body. The computer associated with the scanning device also calculates the trajectory to determine if the line defined by the first locator and the second locator is collinear with the trajectory.
The surgical instrument can also be used in other applications without a first and second locator. For example, the movable member with a passage can be held by a clamp to guide catheters and other surgical instruments into the human body. The clamp includes a pair of cups for holding the movable member. The clamp is spring loaded so that it engages the movable member when the clamp is not held open. Several of the clamps can be held above a patient by individual snake devices or by a support bar that holds a plurality of clamps. A plate that holds several movable members can also be held above the patient or even attached to a patient to provide a platform from which to pass one or more surgical instruments through corresponding movable members. Such arrangements can be used for any type of surgery where it is advantageous to use rigid or flexible type surgical instruments, particularly as might be used in minimally-invasive surgical procedures. The trajectory defined by the trajectory guide and the advancement of the surgical instrument can be controlled from outside the scanning environment.